High minus lens forms

[drk]

I thought this was informative

https://chadwickoptical.com/high-minus-options/

[Elvis Is Alive]

I like that.

I use the lens thickness calculator on this site quite often when a pt wants to know the thickness of a lens with a given frame & material:

http://opticampus.opti.vision/tools/thickness.php

[DanLiv]

Those are really cool lenses. I wish more digital labs put the effort into custom lenticularization like that. I'm sure it's a PIA to do and disruptive to a high volume production lab. But if it were available from my primary labs, instead of small unknown labs, and in premium lenses, instead of all house product, I would use these types a lot more often. Especially for high minus wrpa frames, I've done a handful through specialty labs and they look amazing.

[Fezz]

Here are some other cool options.

http://epiclabsinc.com/

[ChrisBowers]

This formula is incomplete as it’s not considering lens final size. Also, percentages often misled.

[Tallboy]

Dr K this is an awesome tool to teach newbies. Thanks for this!

[drk]

Ignore that. I'm talking about the lens forms.

[Robert Martellaro]

It's a rough but valid estimate.

I understand that the cosmesis is better with the blended surface designs, but I would strongly recommend against using them due to poor tolerance compared to standard lenticulars.

[drk]

I've never done a blended lenticular. So...interesting you have that experience. It does seem weird to blend out a ridge. It seems it would cause a blur ring off center. Who knows what it could do to peripheral acuity? But I guess the minification is so much it could be like looking through a sleazy motel door peeper. It's a "field expander" of sorts.

(Note of interest: in Low Vision Clinic in the days of yore, we would actually have a door peeper to show patients with retinitis pigmentosa. They could hold it up as needed for a quick survey of the scene before walking into an open manhole a la Mr. Magoo. Of course, we never had any real patients.)

[drk]

Well, while we're on the subject of high minus and edge thickness, I've come up with a couple of rules of thumb (That means: rough. That means: go ahead and argue your case):

1. If a VISIBLE minus lens edge exceeds 5mm, it's fugly.
a. that means a plastic eyewire gives you 3-4 mm of bonus
b. that means a semi-rimless or rimless is working against you
c. that means a 1-2 mm metal eyewire helps only a pinch. It's the "neutral state".

2. When doing edge thickness calculations, if the reduction in edge thickness is not greater than a millimeter, it's just not worth it. Two millimeters? Now we're talking.
a. it may be better to set this rule of thumb up as a percentage, such as "if it's not at least 20% thinner, fugedaboudit", but I haven't tested that theory.

[Elvis Is Alive]

Remember, as a general rule of thumb (a few exceptions), thinner lens materials are inferior optically. I always explain this to pts and explain the trade-off. I don't recommend thinner lenses unless there is a 2mm or greater reduction in edge thickness.

Some pts are hyper focused on thickness so I do whatever makes them happy even if it wouldn't be my personal choice.

As we all know, frame selection (A measurement, decentration, etc) plays a huge part in the outer edge thickness for high minus.

[Uncle Fester]

Well, while we're on the subject of high minus and edge thickness, I've come up with a couple of rules of thumb (That means: rough. That means: go ahead and argue your case):

1. If a VISIBLE minus lens edge exceeds 5mm, it's fugly. r u fat shaming?
a. that means a plastic eyewire gives you 3-4 mm of bonus Wear black in layers with a colorful scarf
b. that means a semi-rimless or rimless is working against you embrace the horror
c. that means a 1-2 mm metal eyewire helps only a pinch. It's the "neutral state". Spanx

2. When doing edge thickness calculations, if the reduction in edge thickness is not greater than a millimeter, it's just not worth it. Two millimeters? Now we're talking.
a. it may be better to set this rule of thumb up as a percentage, such as "if it's not at least 20% thinner, fugedaboudit", but I haven't tested that theory.

comments in red

[drk]

Plastic eyewire:






Rimless:

[Uncle Fester]

Her hair at the BET awards was FABULOUS!!!

[AndyOptom]

It's a rough but valid estimate.

I understand that the cosmesis is better with the blended surface designs, but I would strongly recommend against using them due to poor tolerance compared to standard lenticulars.

Seconded (though from your informative posts over the years, this is hardly a surprise!)

Blended lenticulars are something I have almost always failed to switch existing conventional lenticular wearers into, and I dread the day the labs stop making conventional lenticulars.